1. Field of the Invention
This invention relates to apparatus for flattening and withdrawing blown continuous plastic tubular films made by means of a stationary film-blowing head, and more particularly to apparatus that includes flattening plates and squeeze rolls, pivotally movable in mutually opposite senses through at least approximately 360 degrees about the axis of the tubular film, and that permits easier threading of the leading edge of the tubular film upon start up of the film blowing operation.
2. Description of the Prior Art
U.S. Pat. No. 3,768,949 discloses apparatus which serves to spread thicker portions in a tubular film in that the film is wound up like a rope so that cylindrical rolls of film can be formed. In the operation of the known apparatus it is rather difficult after starting the film-blowing plant to thread the leading end of the extruded tubular film between the squeeze rolls and then along a zigzag path between the deflecting rollers and the turning rods, and also between the feed rolls to the winding apparatus. That threading operation requires considerable operator skill because the tubular film that continuously emerges from the annular extrusion die initially has a molten and subsequently a soft plastic consistency and tends to stick.
It is an object of the invention to provide a flattening and take-off apparatus which permits the leading end of the extruded tubular film to be threaded more easily through the apparatus when the film-blowing plant has been started.